Apparatus for placing mold charges in a compression molding machine
An apparatus for placing mold charges into a mold of a compression molding machine includes at least one mold charge pick-up cup for receiving a severed charge of molten plastic, a vacuum source for applying a vacuum to the pick-up cup to retain the mold charge in the cup, and a source of gas (such as air) under pressure for periodically applying gas to the cup to release the mold charge from the cup. In one exemplary embodiment, the vacuum source applies a continuous vacuum to the cup, and the source of gas under pressure periodically applies gas to the cup to overcome the continuous vacuum at the cup. In another exemplary embodiment, vacuum and gas under pressure, are alternately applied to the cup. The vacuum source preferably includes a vacuum generator coupled to the source of gas under pressure for generating the vacuum to be applied to the cup. The vacuum source preferably includes a vacuum pump coupled to the source of gas under pressure for generating the vacuum to be applied to the cup. The source of gas under pressure preferably includes a valve for periodically applying gas under pressure to the cup. The apparatus preferably includes a carrier for moving the cup from a source of severed charges of molten plastic to the mold of the compression molding machine, with the cup, the vacuum pump and the valve preferably being mounted on the carrier. The vacuum source preferably includes a vacuum limiter that also is mounted on the carrier.
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The present disclosure relates to a machine for compression molding plastic articles, such as closure shells or sealing liners within closure shells, and more particularly to an apparatus for placing mold charges into the molds of the compression molding machine.
Machines for compression molding closure shells, or compression molding sealing liners within closure shells, typically include a turret or carousel that rotates around a vertical axis. A plurality of molds are provided around the periphery of the carousel, in the form of male and female mold sections that are aligned along vertical axes parallel to the axis of rotation. Cams drive one or both of the mold sections of each pair between an open position, in which a molded part is stripped from the mold and a charge of molten plastic material is placed into the mold, and a closed position in which the mold sections are brought together to compression mold the shell or liner. In a liner machine, premade shells are placed in a nest when the mold sections are open, and a charge or pellet of liner material is placed within the mold before the mold is closed. U.S. patents that illustrate machines of this type for compression molding plastic closure shells include U.S. Pat. Nos. 5,670,110, 5,989,007, 6,074,583 and 6,478,568. U.S. patents that illustrate machines of this type for compression molding sealing liners within closure shells include U.S. Pat. No. 5,451,360. U.S. application Ser. No. 11/109,374 discloses a vertical wheel compression molding machine, which rotates around a horizontal axis, for compression molding closure shells or sealing liners within closure shells.
The present disclosure involves a number of aspects that can be implemented separately from or in combination with each other.
An apparatus for placing mold charges into a mold of a compression molding machine, in accordance with one aspect of the present disclosure, includes at least one mold charge pick-up cup for receiving a severed charge of molten plastic, a vacuum source for applying a vacuum to the pick-up cup to retain the mold charge in the cup, and a source of gas (such as air) under pressure for periodically applying gas to the cup to release the mold charge from the cup. In one exemplary embodiment, the vacuum source applies a continuous vacuum to the cup, and the source of gas under pressure periodically applies gas to the cup to overcome the continuous vacuum at the cup. In another exemplary embodiment, vacuum and gas under pressure, are alternately applied to the cup. The vacuum source preferably includes a vacuum generator coupled to the source of gas under pressure for generating the vacuum to be applied to the cup. The source of gas under pressure preferably includes a valve for periodically applying gas under pressure to the cup. The apparatus preferably includes a carrier for moving the cup from a source of severed charges of molten plastic to the mold of the compression molding machine, with the cup, the vacuum pump and the valve preferably being mounted on the carrier. The vacuum source preferably includes a vacuum limiter that also is mounted on the carrier.
The mold charge pick-up cup, in accordance with another aspect of the present disclosure, preferably is of annular bellows-shaped construction having a central axis. The bellows-shaped pick-up cup is resiliently bendable laterally of its central axis and resiliently compressible longitudinally of its axis to enhance pick-up of the mold charge and application of vacuum to the mold charge to carry the mold charge to the mold of the compression molding machine. The pick-up cup of annular bellows-shaped construction preferably is of elastomeric construction, most preferably silicone construction.
The disclosure, together with additional objects, features, advantages and aspects thereof, will best be understood from the following description, the appended claims and the accompanying drawings, in which:
The disclosures of U.S. application Ser. Nos. 11/109,374 and 11/156,115 are incorporated herein by reference.
Carrier 320, which preferably is circular, is rotatably coupled to sleeve 322. At least one mold charge placement mechanism 324 is disposed at the periphery of carrier 320 for receiving severed mold charges from extruder nozzle 325, transporting the mold charges to molds 52 in machine 20 (
To the extent thus far described, mold charge placement apparatus 130 is similar to apparatus disclosed in above-referenced U.S. application Ser. Nos. 11/109,374 and 11/156,115, to which reference is made for a more detailed discussion. However, the described structure of molding machine 20 and placement mechanism 130 are given by way of example only in connection with an exemplary implementation of the present disclosure, and the present disclosure is by no means limited to such machine details.
A pneumatic control 400 (
Opening 424 of insert 422 is connected to compressed air control valve 404 (
The disclosure thus has been presented in conjunction with several exemplary embodiments, and a number of additional modifications and variations have been discussed. Other modifications and variations readily will suggest themselves to persons of ordinary skill in the art in view of the foregoing discussion. For example, although the disclosure has been presented in conjunction with a horizontal axis vertical wheel compression molding machine, it will be apparent that the mold charge placement apparatus of the present disclosure can be used equally as well in conjunction with vertical axis carousel-type machines for placing mold charges into the molds of the machine. The disclosure is intended to embrace all such modifications and variations as fall within the spirit and broad scope of the appended claims.
Claims
1. Apparatus for placing mold charges into a mold of a compression molding machine, which includes:
- at least one mold charge pick-up cup for receiving a severed charge of molten plastic,
- a carrier for moving said cup from a source of severed charges of molten plastic to a mold cavity of a compression molding machine,
- a vacuum source for applying vacuum to said pick-up cup to retain a mold charge in said cup, and
- a source of gas under pressure including a valve for periodically applying gas under pressure to said cup to release a mold charge from said cup,
- said vacuum source including a vacuum generator and a vacuum limiter coupled to said source of gas under pressure for generating a continuous vacuum,
- said cup, said vacuum generator, said vacuum limiter and said valve being mounted on said carrier,
- said carrier including a plate for rotation around a first axis, a placement arm mounted on said plate for rotation around a second axis perpendicular to said first axis, said mold charge pick-up cup being mounted on an end of said placement arm for placing mold charges into molds adjacent to a periphery of said plate.
2. The apparatus set forth in claim 1 including a control valve coupled between said mold charge pick-up cup, and said vacuum source and source of gas under pressure, for applying vacuum and gas under pressure alternately to said cup.
3. The apparatus set forth in claim 1 including a pair of said placement arms extending from said plate and a mold charge pick-up cup on an end of each of said arms.
4. The apparatus set forth in claim 1 wherein said mold charge pickup cup is of elastomeric construction.
5. The apparatus set forth in claim 4 wherein said mold charge pick-up cup is of bellows-shaped construction having a central axis, said bellows-shaped construction being resiliently flexible laterally of said central axis and resiliently compressible longitudinally of said central axis.
6. The apparatus set forth in claim 5 wherein said mold charge pick-up cup is of silicone construction.
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Type: Grant
Filed: May 10, 2006
Date of Patent: Apr 15, 2008
Patent Publication Number: 20070264380
Assignee: Owens-Illinois Closures, Inc. (Perrysburg, OH)
Inventors: Wendell D. Willingham (Perrysburg, OH), Daniel L. Mattice (Columbia City, IN), David C. Thompson (Grabill, IN), B. Jack Rote (Sturgis, MI)
Primary Examiner: James P. Mackey
Attorney: Reising, Ethington, Barnes, Kisselle, P.C.
Application Number: 11/431,797
International Classification: B29C 43/34 (20060101);